The present invention relates to power tongs of the type commonly used in oil fields for making up and breaking apart threaded connections between drill pipes, casing, tubing, and the like.
It is frequently necessary in oil field operations to connect or disconnect joints of pipe which are threadedly connected together. Strings of drill pipes, for example, comprise a series of pipe sections joined together at their ends. Power tongs are employed for making up and breaking apart these connections and are used to rotate the pipes relative to each other. A typical power tong includes a mechanism for gripping the external surface of a pipe section and then rotating the pipe section while the pipe section to which it is connected is held stationary or rotated in the opposite direction.
A variety of power tong constructions have been developed for accomplishing this result. U.S. Pat. No. 2,879,680 to Beeman et al, which is commonly assigned with the present application, is illustrative of one type of tong construction. Although devices of this type have proved satisfactory for most oil field operations, extensive use and experimentation has shown that improvements are needed, particularly with respect to the pipe-gripping mechanism and the means for urging the mechanism into contact with the pipe.
Accordingly, an object of the present invention is to provide a power tong for making up and breaking apart joints of drill pipe, casing, tubing, and the like having an improved pipe-gripping mechanism.
Another object of the invention is to provide a power tong having improved means for actuating the pipe-gripping mechanism in order to better grip and rotate the sections of pipe relative to each other.
Yet another object of the invention is to provide a power tong which has an improved camming arrangement for actuating the pipe-gripping mechanism.
These together with other objects and advantages of the invention will become more apparent upon reading the undergoing specification and claims.